Website: Selected readings Topics Introduction to Cell Biology Analysis of Cell Mechanics Cell

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2 Website: Selected readings Topics Introduction to Cell Biology Analysis of Cell Mechanics Cell Mechanics Modeling Measuring Cell Forces Mechanotransduction Grading Homework: 50% Project: 50% No Final 2

3 Date Day # Topic 7-Jan M 1 Introductory - Analysis and Modeling of Cell Mechanics 9-Jan W 2 Introductory - Building Blocks 11-Jan F 3 Introductory - Nucleus 14-Jan M 4 Introductory - Cytoskeleton 16-Jan W 4 Introductory - Cytoskeleton 18-Jan F 5 Introductory - Extracellular Matrix 21-Jan M -- No Class (MLK Day) 23-Jan W 6 Cell Mechanical Analysis - Microneedles 25-Jan F 7 Cell Mechanical Analysis - Micropipette Aspiration 28-Jan M 8 Cell Mechanical Analysis - Atomic Force Microscopy 30-Jan W 9 Cell Mechanical Analysis - Microrheology 1-Feb F -- No Class 4-Feb M -- No Class 6-Feb W -- No Class 8-Feb F 10 Cell Mechanical Analysis - Magnetic Twisting Cytometry 11-Feb M 11 Cell Mechanical Analysis - Optical Tweezers 13-Feb W 12 Modeling Cell Mechanics - Lumped Parameter Viscoelastic Models 15-Feb F 13 Modeling Cell Mechanics - Pure Lipid systems 18-Feb M 14 Modeling Cell Mechanics - Tensegrity 20-Feb W 15 Modeling Cell Mechanics - Foams 22-Feb F 16 Modeling Cell Mechanics - Polymer Networks 25-Feb M 17 Modeling Cell Mechanics - Soft Glassy Material 27-Feb W 18 Modeling Cell Mechanics - Computational Models 1-Mar F 19 Cellular Forces - Adhesions and Traction 4-Mar M 20 Cellular Forces - Traction Force Microscopy 6-Mar W 21 Cellular Forces - MEMS Tools 8-Mar F 22 Mechanotransduction - Introduction & Examples 11-Mar M 23 Mechanotransduction - Whole Cell Analysis 13-Mar W 24 Mechanotransduction - Nanoscale Analysis 15-Mar F 25 Mechanotransduction - Mechanisms 18-Mar M -- Final Project Report Due 3

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5 Micrographia (1665) 5

6 6 The basic functional units of life (composed of numerous components with distinct mechanical characteristics) Origins: Sea Urchin Mouse Seaweed

7 Organ Tissue Cells Proteins m m m m Cells Tissue Animate Basic Unit of Living Things Composed of Proteins Defines structure-function of tissue Sensitive to temperature, radiation, water, ph, nutrients, pressure, ionic strength, osmolarity, hormones, etc. Grains Materials Inanimate Basic Unit of Metal and Ceramics Composed of Atoms Defines structure-strength of material Sensitive to temperature, radiation, corrosion, loading 7

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9 The subject of cell mechanics encompasses a wide range of essential cellular processes, ranging from macroscopic events like the maintenance of cell shape, cell motility, adhesion, and deformation to microscopic events such as how cells sense mechanical signals and transduce them into a cascade of biochemical signals ultimately leading to a host of biological responses. -- Mofrad & Kamm 9

10 10 Diameter: mm (~3 mm for bacteria) Mass: 2-6 x 10-8 g Young s modulus: Pa (CSK: ~ 10-9 Pa) MTC: Magnetic twisting cytometry MA: Micropipette aspiration MM: Micromanipulation (compressive) CP: Cell poking AFM: Atomic force microscopy MBR: Magnetic bead rheometry

11 11 Spectrin network of RBC Tetramers of neo-hookean springs

12 12 Conflicting mindsets: Mechanics treats cells as a material with properties that are time invariant Mechanotransduction illustrates that cells are living, changing entities that alter themselves in response to mechanical stimuli Conceptual Framework: The mechanics of cells and their altered biological functions are intrinsically linked. What are the central structure-function relationships?

13 13 Cell function follows form Cell types: motor neuron osteocyte hair cell adipocyte rods and cones endothelials skeletal muscle smooth muscle RBC lymphocyte epithelial (separated) fibroblasts sperm and egg cells (Drawn to scale)

14 Actin Filaments Myosin Actin Focal Adhesions 10 μm 10 μm 14

15 15 Mechanosensation: Hair cells, touch-sensitive sensory neurons Mechanotransduction: mechanical stimuli that cause a biochemical response

16 Tissue remodeling in response to stress 16

17 watch?v=ren_iqpohjc 17

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19 Cell Shape & Migration 19